The present invention is related to a phone jack coupler which electrically connects one or more telephone sets to a phone jack providing the hookup for two different telephone lines.
Most households have only one telephone line. The line is first brought in by the phone company to a terminal box outside the house and then brought into the house and wired to a desired number of phone jacks distributed in various rooms throughout the house. The phone jacks and the interconnecting cables are very likely installed altogether when the house is built or renovated. The interconnection is such that the pin configuration in all the phone jacks is the same, so that a telephone set can be hooked up to the phone line by plugging into any one of the phone jacks with a telephone cable.
In general, a phone jack has four exposed pins seated in a row in its receiving end, to provide electrical contact to the exposed pins on the phone cable plug. Currently, a regular one-line telephone set uses only two wires to receive and transmit voice and ringing signals. Thus, only two of the four pins on the phone jack are actually needed to connect a regular phone set to a phone line. Conventionally, the two inner (center) pins of a phone jack and the corresponding pins on the phone plug are used for transmitting signals to and from a regular one-line phone set. Electrically, the two side pins are either opened or each of them is connected to the adjacent inner pin. For use in one-line hookup, a phone cable can have four wires or two wires.
As the use of modems and facsimile machines becomes increasingly common in the ordinary household, many houses are hooked up with two telephone lines. When a household requests for an additional phone line, the phone company usually adds the new line (line 2) to the same terminal box so that the two side or outer pins of the phone jack carry the signals for line 2 while the two inner pins carry the signals the original line (line 1). By doing so, the two telephone lines (line 1 and line 2) are accessible from any of the original installed phone jacks in the house without rewiring the house's interior. However, if one hook up a regular telephone set to a phone jack, only line 1 can be accessed. To use line 2, one could hook up a two-line telephone set and choose the "line 2" setting on the set. Alternatively, one could change the wiring behind the phone jack, or switch the wires in a phone cable by cutting the cable and reconnect the wires differently to allow signals from line 2 to reach a regular one-line phone set. It should be noted that, after a cable or a phone jack is altered, it can no longer be used to hook up a regular phone set to line 1.
It is desirable to provide a dual-line phone jack coupler so that a regular telephone set can be hooked up to line 2 without changing the interconnection behind a phone jack, or cutting up a cable to reconnect the Wire. Moreover, it is desirable to have a coupler that comprises two receiving ends, or receptacles, each provides connection to a different telephone line.